Anionic conjugated polytriazole: direct preparation, aggregation-enhanced emission, and highly efficient Al³⁺ sensing

The anionic polytriazole PI with a weight-average molecular weight of 190 300 was facilely and directly prepared in an excellent yield of 98.1% in 6 h by the well-established Cu(I)-catalyzed click polymerization of 4,4′-diazido-2,2′-stilbenedisulfonic acid disodium salt hydrate (1) and AIE-active tetraphenylethene (TPE)-containing diyne (2) under mild reaction conditions. PI is soluble in high polar solvents, and thermally stable with 5% loss of its weight at temperatures higher than 290 °C. The photo-physical property investigation showed that PI possesses the unique feature of aggregation-enhanced emission (AEE). By taking this feature, PI could be used for the specific detection of aluminum ions with a threshold as low as 31 ppb, which could potentially be used for strict drinking water purity control of the aluminum ion content.